Anti-blocking device for slag flushing pipe of wet-process phosphoric acid filtering system

Abstract

The utility model discloses a kind of wet-process phosphoric acid filter system slag flushing water pipe's anti-blocking device, it is characterized in that, including filter, filter outside is provided with cylindrical filter shell (), inside is provided with tangent feed structure;Filter housing (2) is provided with filter cartridge (2) in filter housing (2) top, round hole filter structure is set on filter cartridge (2) surface, slag flushing water outlet (1) is provided with in filter cartridge (2) top, filter housing (2) bottom is provided with conical slag discharge port (2), in filter side still be provided with slag flushing water inlet (5), the slag flushing water inlet (5) is vertically inserted into filter housing (2);The device is two filters and is installed in parallel, and each filter inlet and outlet pipeline is configured independent valve group, and the outlet pipeline of two filters is finally converged to total outlet valve (9);Automatic backwash system is also provided in filter inside.

Description

Technical Field

[0001] This utility model relates to the field of wet-process phosphoric acid production, specifically to an anti-clogging device for the flushing water pipe of a wet-process phosphoric acid filtration system. Background Technology

[0002] In wet-process phosphoric acid production, the filtration system is a core component. Its flushing water pipeline is primarily used to rinse the filter cloth, ensuring its regeneration and filtration efficiency. However, current production technologies typically use recycled or circulating water for flushing. Due to its high hardness and suspended solids content, scale easily forms on the inner walls of pipes and equipment surfaces after prolonged operation. This scale detaches under thermal expansion and contraction or water flow, clogging filter cartridges and flushing water nozzles. This results in unclean filter cloths, reduced regeneration efficiency, and consequently, impacts phosphoric acid production efficiency and phosphorus yield. Furthermore, frequent clogging requires manual cleaning during shutdowns, increasing labor intensity and operational risks (such as chemical burns and mechanical injuries) and causing capacity losses. Therefore, it is necessary to find a process pipeline and equipment that can mitigate scaling and effectively intercept scale and suspended solids to reduce the clogging rate of flushing water nozzles, enabling rapid filter cloth regeneration and reducing worker workload. Utility Model Content

[0003] The purpose of this invention is to provide an anti-clogging device for the flushing water pipe of a wet phosphoric acid filtration system that can slow down scaling and effectively intercept scale and suspended solids, thereby reducing the clogging rate of the flushing water nozzles, enabling rapid regeneration of the filter cloth, and reducing the labor intensity of workers.

[0004] The technical solution of this utility model is as follows: This utility model discloses an anti-clogging device for the flushing water pipe of a wet-process phosphoric acid filtration system, comprising a filter, an external cylindrical filter shell, and an internal tangential feed structure; a filter cylinder is located at the top of the filter shell, with a perforated filter structure on its surface, a flushing water outlet at the top of the filter cylinder, a conical slag discharge port at the bottom of the filter shell, and a flushing water inlet on the side of the filter, the flushing water inlet being vertically inserted into the filter shell; the device consists of two filters installed in parallel, each filter having independent valve groups for its inlet and outlet pipes, and the outlet pipes of the two filters ultimately converging at a main outlet valve; an automatic backwashing system is also installed inside the filter.

[0005] The cylindrical filter housing and tangential feed structure provide a closed filtration space. Tangential feed utilizes centrifugal force to move particles along the filter wall, reducing direct impact on the filter cartridge and lowering the risk of clogging. The filter cartridge and perforated filter structure are the core filtration components. The perforated holes intercept large particles (≥2.5mm), while small particles pass through with the water flow, preventing nozzle clogging. The flushing water outlet and conical slag discharge port are located at the top of the filter cartridge to ensure smooth water flow after filtration. The conical slag discharge port collects settled particles for regular discharge. The flushing water inlet is vertically fed to avoid direct water scouring of the filter cartridge, extending its service life. Two filters are installed in parallel with the main outlet valve to achieve one in use and one on standby. The main outlet valve controls the water output, and when one filter is clogged, it switches to the other to ensure continuous operation. Independent valve groups control the water inlet, outlet, and slag discharge of each filter. The automatic backwashing system triggers reverse cleaning through pressure difference, reducing manual intervention.

[0006] Furthermore, the filter cartridge is made of 5mm thick 904L stainless steel and is fixedly connected to the outlet flange by welding. The distance between the outer edge of the filter cartridge and the inner wall of the filter housing is 20-30mm. 904L stainless steel is resistant to erosion and corrosion and is suitable for the high hardness and high corrosiveness environment of flushing water. The welding connection and the 20-30mm distance ensure the sealing between the filter cartridge and the outlet flange, prevent short circuit of unfiltered liquid, and avoid collision between the outer edge of the filter cartridge and the housing.

[0007] Furthermore, the feed pipe axis of the tangential feed structure is tangent to the cross-section of the filter housing, and the inner diameter of the feed pipe is DN100, which maximizes the centrifugal force effect and makes the particles adhere tightly to the filter wall and settle. The DN100 inner diameter is adapted to the slag flushing water flow requirements. The installation angle is 5° downward horizontally, which balances the feed flow rate and settling efficiency and avoids turbulence interfering with filtration.

[0008] Furthermore, the parallel-installed filters are connected by pipes to form a dual-loop system. Each loop is equipped with: an inlet valve to control the water intake of a single filter and to close the faulty loop when switching; an outlet valve to regulate the filtered water flow and to close during backwashing to create reverse pressure; and a sludge discharge valve, which is installed at the bottom of the conical sludge discharge port for bottom sludge discharge, and works with the conical structure to thoroughly remove scale.

[0009] Furthermore, corrosion-resistant pressure gauge sets are installed at the inlet of the slag flushing water and the outlet of the filter outlet valve, respectively. The corrosion-resistant pressure gauge sets include two pressure gauges, each with a range of 0-1.0 MPa, which reflect the degree of filter cartridge blockage in real time. The 0-1.0 MPa range is adapted to the pressure range of the slag flushing water.

[0010] Furthermore, the automatic backwashing system includes a pressure sensor, a PLC controller, and a high-pressure nozzle array. It is triggered by pressure difference. When the pressure difference between the two filters reaches 0.15 MPa, the system automatically switches to the standby filter. The automatic switching when the pressure difference reaches 0.15 MPa avoids delays caused by manual judgment. During backwashing, a high-velocity water flow is generated to peel off the deposits on the surface of the filter cartridge.

[0011] Furthermore, the circular holes of the filter cartridge are arranged in an equilateral triangular pattern to evenly distribute the pores, avoid local stress concentration, improve the strength of the filter cartridge, and the hole spacing is twice the hole diameter to prevent adjacent hole walls from becoming weak, while maximizing the effective filtration area.

[0012] Furthermore, the cone angle of the conical discharge port is 60° to optimize the particle sliding angle, reduce residue, and avoid incomplete discharge. The height is 1 / 3 of the diameter of the filter shell to balance the discharge efficiency and equipment volume, and to prevent the cone from being too high and increasing costs. The discharge port is equipped with a flange sealing structure to prevent liquid leakage during discharge and improve the safety of the on-site environment.

[0013] In addition, the filter housing is made of carbon steel to provide structural support and meet the mechanical strength requirements of industrial environments. The inner wall is lined with a mm thick rubber lining. The lining material is a composite layer of natural rubber and nitrile rubber. Natural rubber is wear-resistant, nitrile rubber is oil-resistant, and the composite layer is suitable for the complex composition of slag flushing water.

[0014] In addition, the pipe connections of the parallel-installed filters are equipped with detachable flanges, which facilitates filter maintenance or replacement, reduces overall disassembly time, and the flange sealing surface adopts a convex structure and is equipped with a metal spiral wound gasket to improve sealing reliability under high pressure and corrosive environments and prevent leakage.

[0015] In summary, due to the adoption of the above technical solution, the beneficial effects of this utility model are: 1. The present invention relates to an anti-clogging device for the flushing water pipe of a wet phosphoric acid filtration system. The filter cartridge is made of 5mm thick 90L stainless steel and has a round hole structure, which effectively intercepts large particles (≥2.5mm) while small particles pass through with the water flow, avoiding nozzle clogging. At the same time, a tangential feeding structure is set up to use centrifugal force to make the particles settle along the wall of the device, reducing clogging caused by direct flushing of the filter cartridge.

[0016] 2. The parallel dual-circuit design of this utility model supports one in use and one in standby. When one is blocked, it automatically switches to the other to ensure continuous operation.

[0017] 3. This utility model is equipped with an automatic backwashing system, which monitors the inlet and outlet pressures in real time through a set of anti-corrosion pressure gauges to provide a precise trigger signal for backwashing. The automatic backwashing system is triggered by pressure difference and does not require manual judgment. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of a single filter in the anti-clogging device of the slag flushing water pipe of a wet phosphoric acid filtration system according to the present invention.

[0019] Figure 2 This is a schematic diagram of the dual filters connected in parallel according to this utility model.

[0020] Attached reference numerals: 1-Slag flushing water outlet, 2-Filter cartridge, 3-Filter housing, 4-Slag discharge port, 5-Slag flushing water inlet, 6A / 6B-Inlet valve A / B, 7A / 7B-Outlet valve A / B, 8A / 8B-Slag discharge valve A / B, 9-Main outlet valve. Detailed Implementation

[0021] It should be noted that relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0022] The features and performance of this utility model will be further described in detail below with reference to the embodiments.

[0023] like Figures 1-2 As shown, two filters are installed in parallel. Corrosion-resistant pressure gauges are installed at the pump outlet and the outlet of the first valve of the filter, respectively. When the pressure of one filter increases, the filter can be backwashed by the pressure water at the outlet of the other filter.

[0024] I. System Operating Principles and Filtering Mechanisms: This solution addresses the issues of filter operating efficiency and pipe scaling in blast furnace slag flushing water treatment systems, proposing systematic optimization measures. Slag flushing water is delivered to the filter via a dedicated pipeline, where it flows tangentially under the control of the inlet valve. Centrifugal sedimentation causes large particles to settle along the filter wall into the conical slag collection hopper. The filter element employs a multi-layer stainless steel sintered mesh structure, effectively intercepting solid particles larger than the nozzle orifice diameter, ensuring that small particles pass through smoothly without clogging the subsequent spraying system. The system is configured with dual filters operating in parallel. When the pressure difference between the inlet and outlet of the operating filter exceeds a set threshold due to filter screen clogging, it automatically switches to the standby filter to ensure continuous production.

[0025] II. Optimization of Backwashing Regeneration Technology: The regeneration operation employs a dual triggering mechanism of timing and differential pressure. Taking the regeneration of filter A as an example: Preliminary preparations: Confirm that filter B is in normal working order and that the system pressure is stable; Isolation phase: Close the inlet valve of filter A, open the slag discharge valve and bypass outlet valve to block the main process medium; Backwashing stage: Use the residual pressure of the system to perform a short-term backwash (-5 seconds) to discharge the impurities accumulated on the surface of the filter screen through the sludge discharge channel; Reset phase: First, open the main outlet valve 9 to establish system pressure, then close the bypass valve to complete the process switch.

[0026] The key control point is that the regeneration operation must be performed at the initial stage of the standby filter's operation, when the system pressure is high, ensuring sufficient backwashing energy. If both filters are close to being clogged, the system pressure will be lower than the minimum required for regeneration, resulting in incomplete flushing.

[0027] III. Pipeline System Upgrade and Renovation Plan: To address the issues of severe pipe scaling and rapid degradation of chemical cleaning effectiveness in the original system, the following modifications were implemented: Pipe material upgrade: The original carbon steel pipes are replaced with ultra-high molecular weight polyethylene (UHMWPE) lined steel pipes. The material’s extremely low coefficient of friction (0.07-0.12) and excellent corrosion resistance significantly reduce the deposition of calcium and magnesium ions in the slurry on the pipe wall. Flow field optimization design: The pipeline direction is adjusted through CFD flow field simulation to eliminate low velocity zones, and the pipeline diameter is appropriately increased (the main pipeline DN200 is changed to DN250, and the branch pipeline DN100 is changed to DN150) to reduce the intensity of fluid turbulence. Lining process improvement: A hot-melt lining process is adopted to ensure that the bonding strength between the lining layer and the steel pipe substrate is ≥1.5MPa, thus avoiding lining detachment due to temperature changes during operation; Connection optimization: Flange connections are used instead of welding in key parts, and EPDM gaskets are provided to improve the airtightness of the system and reduce maintenance difficulty.

[0028] IV. Enhancement of overall system benefits: The following optimizations are expected to be achieved after the modification: Improved filtration efficiency: Through optimized filter element structure and improved backwashing procedures, the effective operating cycle of the filter is extended by more than 30%. Reduced maintenance costs: The service life of polymer-lined pipes is extended by 2-3 times compared to the original pipes, and the annual chemical cleaning frequency is reduced from 12 times to 8 times. Enhanced system stability: Intelligent switching between dual filters combined with optimized pipeline flow field ensures that the pressure fluctuation of the flushing water supply is ≤0.1MPa; Significant environmental benefits: Reduces the amount of cleaning agents used and wastewater discharged, meeting the requirements for ultra-low emission transformation in the steel industry.

[0029] V. Implementation Safeguard Measures: Establish an online differential pressure monitoring system for filters to provide real-time early warning of clogging risks; Develop standardized regeneration operating procedures and conduct specialized training for operators; Equip a portable endoscope inspection device to regularly check the integrity of the pipe lining; Establish a dynamic spare parts management mechanism to ensure sufficient inventory of key components such as filter elements and seals.

[0030] The embodiments described above merely illustrate specific implementation methods of this application, and while the descriptions are detailed and specific, they should not be construed as limiting the scope of protection of this application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the technical solution of this application, and these modifications and improvements all fall within the scope of protection of this application.

Claims

1. A device for preventing clogging of the flushing water pipe in a wet phosphoric acid filtration system, characterized in that, The device includes a filter, which has a cylindrical filter housing (3) on the outside and a tangential feed structure on the inside. A filter cylinder (2) is set on the top of the filter housing (3), and a circular hole filter structure is set on the surface of the filter cylinder (2). A flushing water outlet (1) is set on the top of the filter cylinder (2), and a conical slag discharge port (4) is set on the bottom of the filter housing (3). A flushing water inlet (5) is also set on the side of the filter, and the flushing water inlet (5) is vertically inserted into the filter housing (3). The device consists of two filters installed in parallel. Each filter has an independent valve group configured for its inlet and outlet pipes. The outlet pipes of the two filters eventually converge to the main outlet valve (9). An automatic backwashing system is also set inside the filter.

2. The anti-clogging device according to claim 1, characterized in that: The filter cartridge (2) is made of 5mm thick 90L stainless steel and is fixedly connected to the outlet flange by welding. The distance between the outer edge of the filter cartridge and the inner wall of the filter housing is 20-0mm.

3. The anti-clogging device according to claim 1, characterized in that: The feed pipe axis of the tangential feed structure is tangent to the cross-section of the filter housing (3), the inner diameter of the feed pipe is DN100, and the installation angle is 5° downward horizontally.

4. The anti-clogging device according to claim 1, characterized in that: The parallel-installed filters are connected by pipes to form a dual-loop system. Each loop is equipped with: an inlet valve (6A, 6B), an outlet valve (7A, 7B), and a slag discharge valve (8A, 8B), wherein the slag discharge valve is installed at the bottom of the conical slag discharge port (4).

5. The anti-clogging device according to claim 1, characterized in that: A corrosion-resistant pressure gauge set is installed at the outlet of the slag flushing water inlet (5) and the filter outlet valve (7A, 7B), respectively. The corrosion-resistant pressure gauge set includes two pressure gauges, each with a range of 0-1.0 MPa.

6. The anti-clogging device according to claim 1, characterized in that: The automatic backwashing system includes a pressure sensor, a PLC controller, and a high-pressure nozzle array. It is triggered by a pressure difference. When the pressure difference between the two filters reaches 0.15 MPa, the system automatically switches to the standby filter.

7. The anti-clogging device according to claim 1, characterized in that: The filter cartridge (2) has circular holes arranged in an equilateral triangle pattern, with the hole spacing being twice the hole diameter.

8. The anti-clogging device according to claim 1, characterized in that: The cone angle of the cone discharge port (4) is 60°, and the height is 1 / of the diameter of the filter shell. The cone discharge port (4) is equipped with a flange sealing structure.

9. The anti-clogging device according to claim 1, characterized in that: The filter housing (3) is made of carbon steel and has a mm thick rubber lining on the inner wall. The lining material is a composite layer of natural rubber and nitrile rubber.

10. The anti-clogging device according to any one of claims 1-9, characterized in that: The pipe connections of the filters installed in parallel are equipped with detachable flanges, and the flange sealing surfaces have a convex structure and are fitted with metal spiral wound gaskets.

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